<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>用户登录系统</title>
    <script src="js/jquery-1.9.1.min.js"></script>
</head>
<body>
    <div style="margin-top:50px;margin-left:40%">
        <h1 style="padding-left:50px">用户登录</h1>
        姓名:<input id="username" type="text" name="username">
        <p>
            密码:<input id="password" type="password" name="password">
        <p>
        <div style="padding-left:50px">
            <input  type="button" value="提 交" onclick="mySubmit()">&nbsp;&nbsp;&nbsp;&nbsp;
            <input type="reset" value="重 置">
        </div>
    </div>
<script>
     function mySubmit(){
      <!-- 非空效验  -->
      var username=jQuery("#username");
      var password=jQuery("#password");
      if("" == username.val()){
           alert("请先输入用户名!")
           username.focus();
           return;
      }
      if(""==password.val()){
            alert("请先输入密码!");
            return;
      }
         jQuery.ajax({
             url:"login",//设置请求地址
             type:"POST",//设置请求方法类型
             contentType:"application/x-www-form-urlencoded; charset=utf-8",//请求类型
             //dataType:"",//响应的类型
             data:{"username":username.val(),"password":password.val()},
             success:function(data){

                  alert(data);
             }
         });
     }
</script>
</body>
</html>